Dresden 2011 – scientific programme

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MO: Fachverband Molekülphysik

MO 17: Quantum Control

MO 17.2: Talk

Wednesday, March 16, 2011, 16:45–17:00, TOE 317

Femtosecond Pulse-Shaping and Characterization in the Mid-Infrared — •Rene Costard, Christian Greve, Erik T. J. Nibbering, and Thomas Elsaesser — Max Born Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max Born Strasse 2A, D-12489 Berlin, Germany

Femtosecond mid-infrared (IR) pulses are now commonly used for nonlinear time-resolved vibrational spectroscopy. Pump-probe or multidimensional photon echo experiments of transient vibrational excitations allow for elucidation of anharmonic couplings and vibrational energy flow pathways. So far, these experiments have typically been performed using the output of a parametric frequency converter, with the central frequency of the IR pulses as experimental parameter. Controlling the amplitude and phase of these pulses, however, allow for a full coherent control of vibrational excitations in molecular systems. We present experimental results of amplitude and phase shaping of ultrashort pulses around 3 µm, which are generated by taking the idler output of an optical parametric amplifier using KTP, pumped by a Ti:sapphire chirped-pulse amplification system. Directing these pulses through a 4f setup with a germanium acousto-optic modulator in the Fourier plane, enables independent shaping of amplitude and phase to generate e.g. double pulses with adjustable time separation or arbitrarily chirped pulses. We fully characterize the amplitude and phase of these shaped mid-IR pulses by cross-correlation frequency-resolved optical gating (XFROG) with well-characterized 800 nm pulses.